The present invention relates to resin compositions comprising a phosphoramide compound having a glass transition temperature of at least about 0xc2x0 C., preferably of at least about 10xc2x0 C., and most preferably of at least about 20xc2x0 C. The invention also relates to methods to make the resin compositions and articles made from the resin compositions.
Compounds containing phosphorus have been used in resin compositions for a variety of reasons. For example, various phosphites have been utilized to enhance the melt stability and/or color stability of resin compositions. Alternatively, various organic phosphate esters have been utilized in resin compositions to improve the flame resistance properties of the compositions and/or to enhance the melt flow characteristics of the compositions. Certain water soluble phosphoramides have also been used in the textile industry as flame retardant finishes for fabrics.
As part consolidation and weight reduction continues to evolve in many industries, the physical property demands placed upon resin manufacturers are increasing. Key industries increasing the demands include the electronics and computer industries, especially for computer housings, computer monitor housings, and printer housings. One increasing demand is for materials that possess higher heat resistance while preferably substantially retaining other key physical properties. Another increasing demand is for materials that are rated in the Underwriter""s Laboratory UL-94 test protocol as V-0, V-1, or V-2. It is therefore apparent that new resin compositions that meet these and other demands continue to be sought.
The present invention provides flame retardant resin compositions comprising the following and any reaction products thereof:
a) at least one thermoplastic resin;
b) at least one phosphoramide having a glass transition point of at least about 0xc2x0 C., preferably of at least about 10xc2x0 C., and most preferably of at least about 20xc2x0 C., of the formula: 
wherein Q1 is oxygen or sulfur; R1 is an amine residue, and R2 and R3 are each independently an alkyloxy, alkylthio, aryloxy, or arylthio residue, or an aryloxy or arylthio residue containing at least one alkyl substitution; or an amine residue; and
c) at least one adjunct flame retardant compound.
The present invention also provides articles made from the resin compositions. Furthermore, the present invention provides methods to make resin compositions having improved heat and/or processability over compositions known in the art.
The major constituent of the compositions of the invention is at least one thermoplastic polymer. Both addition and condensation polymers are included. Illustrative, non-limiting examples of thermoplastic polymers are olefin polymers such as polyethylene and polypropylene; diene polymers such as polybutadiene and polyisoprene; polymers of ethylenically unsaturated carboxylic acids and their functional derivatives, including acrylic polymers such as poly(alkyl acrylates), poly(alkyl methacrylates), polyacrylamides, polyacrylonitrile and polyacrylic acid; alkenylaromatic polymers such as polystyrene, poly-alpha-methylstyrene, polyvinyltoluene, rubber-modified polystyreries, and the like; polyamides such as nylon-6 and nylon-66; polyesters; polycarbonates; and polyarylene ethers.
Both thermoplastic and thermoplastic elastomeric polyesters are suitable for use in the present invention. Illustrative, non-limiting examples of thermoplastic polyesters include poly(ethylene terephthalate), poly(1,4-butylene terephthalate), poly(1,3-propylene terephthalate), polycyclohexanedimethanol terephthalate, polycyclohexanedimethanol-co-ethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, and polyarylates. Illustrative, non-limiting examples of thermoplastic elastomeric polyesters (commonly known as TPE) include polyetheresters such as poly(alkylene terephthalate)s (particularly poly[ethylene terephthalate] and poly[butylene terephthalate]) containing soft-block segments of poly(alkylene oxide), particularly segments of poly(ethylene oxide) and poly(butylene oxide); and polyesteramides such as those synthesized by the condensation of an aromatic diisocyanate with dicarboxylic acids and a carboxylic acid-terminated polyester or polyether prepolymer.
Suitable polyarylates include, but are not limited to, the polyphthalate esters of 2,2-bis(4-hydroxyphenyl)propane (commonly known as bisphenol A), and polyesters consisting of structural units of the formula II: 
wherein R4 is hydrogen or C1-4 alkyl, optionally in combination with structural units of the formula III: 
wherein R5 is a divalent C4-12 aliphatic, alicyclic or mixed aliphatic-alicyclic radical. The latter polyesters are prepared by the reaction of a 1,3-dihydroxy-benzene with at least one aromatic dicarboxylic acid chloride under alkaline conditions. Structural units of formula II contain a 1,3-dihydroxybenzene moiety which may be substituted with halogen, usually chlorine or bromine, or preferably with C1-4 alkyl; e.g., methyl, ethyl, isopropyl, propyl, butyl. Said alkyl groups are preferably primary or secondary groups, with methyl being more preferred, and are most often located in the ortho position to both oxygen atoms although other positions are also contemplated. The most preferred moieties are resorcinol moieties, in which R4 is hydrogen. Said 1,3-dihydroxybenzene moieties are linked to aromatic dicarboxylic acid moieties which may be monocyclic moieties, e.g., isophthalate or terephthalate, or polycyclic moieties, e.g., naphthalenedicarboxylate. Preferably, the aromatic dicarboxylic acid moieties are isophthalate and/or terephthalate: either or both of said moieties may be present. For the most part, both are present in a molar ratio of isophthalate to terephthalate in the range of about 0.25-4.0:1, preferably about 0.8-2.5:1.
In the optional soft block units of formula II resorcinol or alkylresorcinol moieties are again present in ester-forming combination with R5 which is a divalent C4-12 aliphatic, alicyclic or mixed aliphatic-alicyclic radical. It is preferably aliphatic and especially C8-12 straight chain aliphatic. A particularly preferred arylate polymer containing soft block units is one consisting of resorcinol isophthalate and resorcinol sebacate units in a molar ratio between 8.5:1.5 and 9.5:0.5.
Polycarbonates useful in the compositions of the invention include those comprising structural units of the formula IV: 
wherein at least about 60 percent of the total number of R6 groups are aromatic organic radicals and the balance thereof are aliphatic, alicyclic, or aromatic radicals. More preferably, R6 is an aromatic organic radical and still more preferably a radical of the formula V:
xe2x80x94A1xe2x80x94Y1xe2x80x94A2xe2x80x94xe2x80x83xe2x80x83(V)
wherein each A1 and A2 is a monocyclic divalent aryl radical and Y1 is a bridging radical in which one or two atoms, separate A1 from A2. The preferred embodiment is one in which one atom separates A1 from A2. Illustrative non-limiting examples of radicals of this type are xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94S(O)xe2x80x94 or xe2x80x94SO2)xe2x80x94, xe2x80x94C(O)xe2x80x94, methylene, cyclohexyl-methylene, 2-[2.2.1]-bicycloheptylidene, ethylidene, isopropylidene, neopentylidene, cyclohexylidene, 3,3,5-trimethylcyclohexylidene, cyclopentadecylidene, cyclododecylidene, and adamantylidene. The bridging radical Y1, is most often a hydrocarbon group and particularly a saturated group such as methylene, cyclohexylidene, 3,3,5-trimethylcyclohexylidene, or isopropylidene.
Preferred polycarbonates are derived from dihydric phenols in which only one atom separates A1 and A2. Some illustrative, non-limiting examples of dihydric phenols include the dihydroxy-substituted aromatic hydrocarbons disclosed by name or formula (generic or specific) in U.S. Pat. No. 4,217,438, which is incorporated herein by reference. Some preferred examples of dihydric phenols include 2,2-bis(4-hydroxyphenyl)propane (commonly known as bisphenol A); 4,4xe2x80x2-(3,3,5-trimethylcyclohexylidene)diphenol; 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane; 2,4xe2x80x2-dihydroxydiphenylmethane; bis(2-hydroxyphenyl)methane; bis(4-hydroxyphenyl)methane; bis(4-hydroxy-5-nitrophenyl)methane; bis(4-hydroxy-2,6-dimethyl-3-methoxyphenyl)methane; 1,1-bis(4-hydroxyphenyl)ethane; 1,1-bis(4-hydroxy-2-chlorophenyl)ethane; 2,2-bis(3-phenyl-4-hydroxyphenyl)-propane; bis(4-hydroxyphenyl)cyclohexylmethane; 2,2-bis(4-hydroxyphenyl)-1-phenylpropane; resorcinol; C1-3 alkyl-substituted resorcinols, and 6,6xe2x80x2-dihydroxy-3,3,3xe2x80x2,3xe2x80x2-tetramethyl-1,1xe2x80x2-spirobiindane.
The most preferred polycarbonates are bisphenol A polycarbonates, in which each of A1 and A2 is p-phenylene and Y1 is isopropylidene. Preferably, the weight average molecular weight of the initial polycarbonate ranges from about 5,000 to about 100,000; more preferably from about 10,000 to about 65,000, still more preferably from about 16,000 to about 40,000, and most preferably from about 20,000 to about 36,000. Suitable polycarbonates may be made using any process known in the art, including interfacial, solution, solid-state, or melt processes.
In one embodiment the present invention comprises a composition containing at least one polycarbonate. In another embodiment the invention comprises compositions containing two different polycarbonates. Both homopolycarbonates derived from a single dihydroxy compound monomer and copolycarbonates derived from more than one dihydroxy compound monomer are encompassed. In a preferred embodiment compositions comprise a bisphenol A homopolycarbonate and a copolycarbonate comprising bisphenol A monomer units and 4,4xe2x80x2-(3,3,5-trimethylcyclohexylidene)diphenol monomer units. Preferably, the copolycarbonate comprises 5-65 mole %, more preferably 15-60 mole %, and most preferably 30-55 mole % of 4,4xe2x80x2(3,3,5-trimethylcyclohexylidene)diphenol with the remaining dihydroxy monomer being bisphenol A. The weight ratio of bisphenol A polycarbonate to copolycarbonate comprising bisphenol A monomer units and 4,4xe2x80x2-(3,3,5-trimethylcyclohexylidene)diphenol monomer units in compositions of the present invention is preferably between 95:5 and 70:30 and more preferably between 85:15 and 75:25.
Also suitable for use in the present invention are polyestercarbonates. The polyestercarbonates may generally be termed copolyesters containing carbonate groups, carboxylate groups, and aromatic carbocyclic groups in the polymer chain, in which at least some of the carboxylate groups and at least some of the carbonate groups are bonded directly to ring carbon atoms of the aromatic carbocyclic groups. These polyestercarbonates are, in general, prepared by reacting at least dihydric phenol, at least one difunctional carboxylic acid or reactive derivative of the acid such as the acid dihalide, and a carbonate precursor. Suitable dihydric phenols include, but are not limited to, those named or referred to hereinabove. Some illustrative, non-limiting examples of suitable aromatic dicarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, homophthalic acid, o-, m-, and p-phenylenediacetic acid; and the polynuclear aromatic acids such as diphenic acid, 1,4-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, and the like. These acids may be used either individually, or as a mixture of two or more different acids in the preparation of suitable polyestercarbonates.
The polyestercarbonates which find use in the instant invention and the methods for their preparation are well known in the art as disclosed in, for example, U.S. Pat. Nos. 3,030,331; 3,169,121; 3,207,814; 4,194,038; 4,156,069; 4,238,596; 4,238,597; 4,487,896; 4,506,065, and in copending application Ser. No. 09/181,902, filed Oct. 29, 1998, and assigned to the same assignee as the instant application, all of which are hereby incorporated by reference. Among the properties characterizing these polymers is a relatively high distortion temperature under load (DTUL) as well as a relatively high impact strength as measured by a notched Izod test protocol.
The polyarylene ethers are most often polyphenylene ethers having structural units of the formula: 
wherein each Q2 is independently halogen, primary or secondary lower alkyl, phenyl, haloalkyl, aminoalkyl, hydrocarbonoxy, or halohydrocarbonoxy wherein at least two carbon atoms separate the halogen and oxygen atoms, and each Q3 is independently hydrogen, halogen, primary or secondary lower alkyl, phenyl, haloalkyl, hydrocarbonoxy or halohydrocarbonoxy as defined for Q2.
Both homopolymer and copolymer polyphenylene ethers are included. The preferred homopolymers are those containing 2,6-dimethyl-1,4-phenylene ether units. Suitable copolymers include random copolymers containing such units in combination with, for example, 2,3,6-trimethyl-1,4-phenylene ether units. Also included are polyphenylene ethers containing moieties prepared by grafting onto the polyphenylene ether in known manner such materials as vinyl monomers or polymers such as polystyrenes and elastomers, as well as coupled polyphenylene ethers in which coupling agents such as low molecular weight polycarbonates, quinones, heterocycles and formals undergo reaction in known manner with the hydroxy groups of two polyphenylene ether chains to produce a higher molecular weight polymer.
The polyphenylene ethers generally have an intrinsic viscosity greater than about 0.1, most often in the range of about 0.2-0.6 and especially about 0.35-0.6 deciliters per gram (dl./g.), as measured in chloroform at 25xc2x0 C.
The polyphenylene ethers are typically prepared by the oxidative coupling of at least one monohydroxyaromatic compound such as 2,6-xylenol or 2,3,6-trimethylphenol. Catalyst systems are generally employed for such coupling; they typically contain at least one heavy metal compound such as a copper, manganese or cobalt compound, usually in combination with various other materials.
Particularly useful polyphenylene ethers for many purposes are those which comprise molecules having at least one aminoalkyl-containing end group. The aminoalkyl radical is covalently bound to a carbon atom located in an ortho position to a hydroxy group. Products containing such end groups may be obtained by incorporating an appropriate primary or secondary monoamine such as di-n-butylamine or dimethylamine as one of the constituents of the oxidative coupling reaction mixture. Also frequently present are 4-hydroxybiphenyl end groups and/or biphenyl structural units, typically obtained from reaction mixtures in which a by-product diphenoquinone is present, especially in a copper-halide-secondary or tertiary amine system. A substantial proportion of the polymer molecules, typically constituting as much as about 90% by weight of the polymer, may contain at least one of said aminoalkyl-containing and 4-hydroxy-biphenyl end groups. It will be apparent to those skilled in the art from the foregoing that the polyphenylene ethers contemplated for use in the invention include all those presently known, irrespective of variations in structural units or ancillary chemical features.
Both homopolymer and copolymer thermoplastic polymers are included in the compositions of the present invention. Copolymers may include random, block or graft type. Thus, for example, suitable polystyrenes include homopolymers, such as amorphous polystyrene and syndiotactic polystyrene, and copolymers. The latter embraces high impact polystyrene (HIPS), a genus of rubber-modified polystyrenes comprising blends and grafts wherein the rubber is a polybutadiene or a rubbery copolymer of about 70-98% styrene and 2-30% diene monomer. Also included are ABS copolymers, which are typically grafts of styrene and acrylonitrile on a previously formed diene polymer backbone (e.g., polybutadiene or polyisoprene). Suitable ABS copolymers may be produced by any methods known in the art. Especially preferred ABS copolymers are typically produced by mass polymerization (often referred to as bulk ABS) or emulsion polymerization (often referred to as high rubber graft ABS).
The preferred thermoplastic polymers for many purposes are polyesters, polycarbonates, polyphenylene ethers, polystyrene resin, high impact polystyrene resin (HIPS), and styrene-acrylonitrile copolymers (SAN), including ABS copolymers. These may be employed individually or as blends. Especially preferred blends include those of polyphenylene ether with at least one of HIPS, amorphous polystyrene, and syndiotactic polystyrene; and polycarbonate blends with at least one of ABS, SAN, and polyester.
In resinous compositions there is often an improvement in melt flow and/or other physical properties when one molecular weight grade of at least one resinous constituent is combined with a relatively lower molecular weight grade of similar resinous constituent. Illustrative, non-limiting examples include compositions containing polycarbonate, polyphenylene ether, thermoplastic polyester, thermoplastic elastomeric polyester, or polyamide. For example, in a polycarbonate-containing blend there is often an improvement in melt flow when one molecular weight grade of polycarbonate is combined with a proportion of a relatively lower molecular weight grade of similar polycarbonate. Therefore, the present invention encompasses compositions comprising only one molecular weight grade of a particular resinous constituent and also compositions comprising two or more molecular weight grades of similar resinous constituent. When two or more molecular weight grades of similar resinous constituent are present, then the weight average molecular weight of the lowest molecular weight constituent is about 10% to about 95%, preferably about 40% to about 85%, and more preferably about 60% to about 80% of the weight average molecular weight of the highest molecular weight constituent. In one representative, non-limiting embodiment polycarbonate-containing blends include those comprising a polycarbonate with weight average molecular weight between about 28,000 and about 32,000 combined with a polycarbonate with weight average molecular weight between about 16,000 and about 26,000. When two or more molecular weight grades of similar resinous constituent are present, the weight ratios of the various molecular weight grades may range from about 1 to about 99 parts of one molecular weight grade and from about 99 to about 1 parts of any other molecular weight grades. A mixture of two molecular weight grades of a resinous constituent is often preferred, in which case the weight ratios of the two grades may range from about 99:1 to about 1:99, preferably from about 80:20 to about 20:80, and more preferably from about 70:30 to about 50:50. Since not all manufacturing processes for making a particular resinous constituent are capable of making all molecular weight grades of that constituent, the present invention encompasses compositions comprising two or more molecular weight grades of similar resinous constituent in which each of the similar resins is made by a different manufacturing process. In one particular embodiment the instant invention encompasses compositions comprising a polycarbonate made by an interfacial process in combination with a polycarbonate of different weight average molecular weight made by a melt process.
Another constituent of the resin compositions of the invention is at least one phosphoramide having a glass transition point of at least about 0xc2x0 C., preferably of at least about 10xc2x0 C., and most preferably of at least about 20xc2x0 C., of the formula I: 
wherein Q1 is oxygen or sulfur; R1 is an amine residue, and R2 and R3 are each independently an alkyloxy, alkylthio, aryloxy, or arylthio residue, or an aryloxy or arylthio residue containing at least one alkyl or halogen substitution, or mixture thereof; or an amine residue.
It should be noted that in the descriptions herein, the words xe2x80x9cradicalxe2x80x9d and xe2x80x9cresiduexe2x80x9d are used interchangeably, and are both intended to designate an organic moiety. For example, alkyl radical and alkyl residue are both intended to designate an alkyl moiety. The term xe2x80x9calkylxe2x80x9d as used in the various embodiments of the present invention is intended to designate both normal alkyl, branched alkyl, aralkyl, and cycloalkyl radicals. Normal and branched alkyl radicals are preferably those containing from 1 to about 12 carbon atoms, and include as illustrative non-limiting examples methyl, ethyl, propyl, isopropyl, butyl, tertiary-butyl, pentyl, neopentyl, and hexyl. Cycloalkyl radicals represented are preferably those containing from 3 to about 12 ring carbon atoms. Some illustrative non-limiting examples of these cycloalkyl radicals include cyclobutyl, cyclopentyl, cyclohexyl, methylcyclohexyl, and cycloheptyl. Preferred aralkyl radicals are those containing from 7 to about 14 carbon atoms; these include, but are not limited to, benzyl, phenylbutyl, phenylpropyl, and phenylethyl. Aryl radicals used in the various embodiments of the present invention are preferably those containing from 6 to 12 ring carbon atoms. Some illustrative non-limiting examples of these aryl radicals include phenyl, biphenyl, and naphthyl. The preferred halogen radicals used in the various embodiments of the present invention are chlorine and bromine.
The compositions may contain essentially a single phosphoramide or a mixture of two or more different types of phosphoramides. Compositions containing essentially a single phosphoramide are preferred.
When a phosphoramide having a glass transition point of at least about 0xc2x0 C. is used as a source of phosphorus in resin compositions, it was unexpectedly found that a higher heat deflection temperature of test specimens made from the resin composition could be obtained as compared to compositions containing an organophosphate known in the art for enhancing the processability and/or flame resistance characteristics of the composition.
Although the invention is not dependent upon mechanism, it is believed that selection of R1, R2, and R3 residues that result in restricted rotation of the bonds connected to the phosphorus provide an increased glass transition point in comparison to similar phosphoramides with residues having a lesser degree of restriction. Residues having bulky substituents such as, for example, aryloxy residues, particularly those containing at least one halogen or preferably at least one alkyl substitution, result in phosphoramides having a higher glass transition point than similar phosphoramides without aryloxy residues. Likewise, residues wherein at least two of the R1, R2, and R3 residues are interconnected, such as a neopentyl residue for the combination of the R2 and R3 residues, can lead to desired phosphoramides having a glass transition point of at least about 0xc2x0 C.
In a preferred embodiment, the phosphoramide comprises a phosphoramide having a glass transition temperature of at least about 0xc2x0 C., preferably of at least about 10xc2x0 C., and most preferably of at least about 20xc2x0 C., of the formula VI: 
wherein each Q1 is independently oxygen or sulfur; and each of A3-6 is independently an alkyloxy, alkylthio, aryloxy, or arylthio residue, or an aryloxy or arylthio residue containing at least one alkyl or halogen substitution, or mixture thereof; or an amine residue. In a preferred embodiment each Q1 is oxygen, and each A3-6 is an aryloxy moiety with at least one aryloxy moiety having at least one substituent on an aromatic ring ortho to the oxygen linkage. In a more preferred embodiment each Q1 is oxygen, and each A3-6 moiety is independently an aryloxy moiety with at least one substituent on each aromatic ring ortho to the oxygen linkage, optionally further substituted. In a still more preferred embodiment each Q1 is oxygen, and each A3-6 moiety is independently an aryloxy moiety with at least two substituents on each aromatic ring ortho to the oxygen linkage, as for example a 2,6-disubstituted phenoxy moiety, optionally further substituted. Preferred substituents are C1-8 straight-chain or branched alkyl, or halogen. In an especially preferred embodiment of the invention, each Q1 is oxygen, and each A3-6 moiety is independently phenoxy, 2,6-dimethylphenoxy, 2,3,6-trimethylphenoxy, or 2,4,6-trimethylphenoxy. In a more especially preferred embodiment of the invention, each Q1 is oxygen, and all A3-6 moieties are phenoxy, 2,6-dimethylphenoxy, 2,3,6-trimethylphenoxy, or 2,4,6-trimethylphenoxy. These phosphoramides are piperazine-type phosphoramides. In the above formula wherein each Q1 is oxygen, and each A3-6 moiety is a 2,6-dimethylphenoxy moiety, the glass transition temperature of the phosphoramide is about 62xc2x0 C. and the melting point is about 192xc2x0 C. Also, in the above formula wherein each Q1 is oxygen, and each A3-6 moiety is a 2,3,6-trimethylphenoxy moiety, the glass transition temperature of the phosphoramide is about 61xc2x0 C. and the melting point is about 237-239xc2x0 C. Also, in the above formula wherein each Q1 is oxygen, and each A3-6 moiety is a 2,4,6-trimethylphenoxy moiety, the glass transition temperature of the phosphoramide is about 74xc2x0 C. and the melting point is about 233-234xc2x0 C. Conversely, in the above formula wherein each Q1 is oxygen, and each A3-6 moiety is phenoxy, the glass transition temperature of the phosphoramide is about 0xc2x0 C. and the melting point is about 188xc2x0 C. It was unexpected that the glass transition temperature would be so high for a sterically hindered phosphoramide of formula VI where each Q1 is oxygen, and wherein each of A3-6 is a 2,6-dimethylphenoxy moiety (i.e. about 62xc2x0 C.) as compared to the glass transition temperature of the corresponding phosphoramide of formula VI wherein each Q1 is oxygen, and each of A3-6 is a phenoxy moiety (i.e. about 0xc2x0 C.), especially since the melting points for the phosphoramides differ by only about 4xc2x0 C. For comparison, the glass transition temperature of tetraphenyl resorcinol diphosphate is about xe2x88x9238xc2x0 C. It is also possible to make phosphoramides with intermediate glass transition temperatures by using a mixture of various substituted and non-substituted aryl moieties within the phosphoramide.
In another preferred embodiment, the phosphoramide comprises a phosphoramide having a glass transition temperature of at least about 0xc2x0 C., preferably of at least about 10xc2x0 C., and most preferably of at least about 20xc2x0 C., of the formula VII: 
wherein each Q1 is independently oxygen or sulfur; and each of A7-11 is independently an alkyloxy, alkylthio, aryloxy, or arylthio residue, or an aryloxy or arylthio residue optionally containing at least one alkyl or halogen substitution, or mixture thereof; or an amine residue; and n is from 0 to about 200. In a preferred embodiment each Q1 is oxygen, and each A7-11 moiety is independently phenoxy or a substituted phenoxy moiety. In a more preferred embodiment each Q1 is oxygen, and each A7-11 is an aryloxy moiety with at least one aryloxy moiety having at least one substituent on an aromatic ring ortho to the oxygen linkage. In a still more preferred embodiment each Q1 is oxygen, and each A7-11 moiety is independently an aryloxy moiety with at least one substituent on each aromatic ring ortho to the oxygen linkage, optionally further substituted. In a still more preferred embodiment each Q1 is oxygen, and each A7-11 moiety is independently an aryloxy moiety with at least two substituents on each aromatic ring ortho to the oxygen linkage, as for example a 2,6-disubstituted phenoxy moiety, optionally further substituted. Preferred substituents are C1-8 straight-chain or branched alkyl, or halogen. In an especially preferred embodiment of the invention, each Q1 is oxygen, and each A7-11 moiety is independently phenoxy, 2-methylphenoxy, 2,6-dimethylphenoxy, 2,3,6-trimethylphenoxy, or 2,4,6-trimethylphenoxy, and n is from 0 to about 5. In a more especially preferred embodiment of the invention, each Q1 is oxygen, and all A7-11 moieties are phenoxy, 2-methylphenoxy, 2,6-dimethylphenoxy, 2,3,6-trimethylphenoxy, or 2,4,6-trimethylphenoxy, and n is from 0 to about 5.
In another embodiment of the invention the phosphoramide comprises a phosphoramide having a glass transition temperature of at least about 0xc2x0 C., preferably of at least about 10xc2x0 C., and most preferably of at least about 20xc2x0 C., of the formula VIII: 
wherein each Q1 is independently oxygen or sulfur; and each of A12-17 is independently an alkyloxy, alkylthio, aryloxy, or arylthio residue, or an aryloxy or arylthio residue optionally containing at least one alkyl or halogen substitution, or mixture thereof; or an amine residue. In a preferred embodiment each Q1 is oxygen, and each A12-17 moiety is independently phenoxy or a substituted phenoxy moiety. In a more preferred embodiment each Q1 is oxygen, and each A12-17 is an aryloxy moiety with at least one aryloxy moiety having at least one substituent on an aromatic ring ortho to the oxygen linkage. In a still more preferred embodiment each Q1 is oxygen, and each A12-17 moiety is independently an aryloxy moiety with at least one substituent on each aromatic ring ortho to the oxygen linkage, optionally further substituted. In yet a still more preferred embodiment each Q1 is oxygen, and each A12-17 moiety is independently an aryloxy moiety with at least two substituents on each aromatic ring ortho to the oxygen linkage, as for example a 2,6-disubstituted phenoxy moiety, optionally further substituted. Preferred substituents are C1-8 straight-chain or branched alkyl, or halogen. In an especially preferred embodiment of the invention, each Q1 is oxygen, and each A12-17 moiety is independently phenoxy, 2-methylphenoxy, 2,6-dimethylphenoxy, 2,3,6-trimethylphenoxy, or 2,4,6-trimethylphenoxy. In a more especially preferred embodiment of the invention, each Q1 is oxygen, and all A12-17 moieties are 2-methylphenoxy, 2,6-dimethylphenoxy, 2,3,6-trimethylphenoxy, or 2,4,6-trimethylphenoxy.
In another embodiment of the invention the phosphoramide comprises a phosphoramide having a glass transition temperature of at least about 0xc2x0 C., preferably of at least about 10xc2x0 C., and most preferably of at least about 20xc2x0 C., of the formula IX: 
wherein each Q1 is independently oxygen or sulfur; each of A18-21 is independently an alkyloxy, alkylthio, aryloxy, or arylthio residue, or an aryloxy or arylthio residue optionally containing at least one alkyl or halogen substitution, or mixture thereof; or an amine residue; and each R7 is an alkyl radical, or both R7 radicals taken together are an alkylidene or alkyl-substituted alkylidene radical. In preferred embodiments each Q1 is oxygen, and each A18-21 moiety is independently phenoxy or a substituted phenoxy moiety. In a more preferred embodiment each Q1 is oxygen, and each A18-21 is an aryloxy moiety with at least one aryloxy moiety having at least one substituent on an aromatic ring ortho to the oxygen linkage. In still more preferred embodiments each Q1 is oxygen, and each A18-21 moiety is independently an aryloxy moiety with at least one substituent on each aromatic ring ortho to the oxygen linkage, optionally further substituted. In yet still more preferred embodiments each Q1 is oxygen, and each A18-21 moiety is independently an aryloxy moiety with at least two substituents on each aromatic ring ortho to the oxygen linkage, as for example a 2,6-disubstituted phenoxy moiety, optionally further substituted. Preferred substituents are C1-8 straight-chain or branched alkyl, or halogen. In especially preferred embodiments of the invention, each Q1 is oxygen, and each A18-21 moiety is independently phenoxy, 2-methylphenoxy, 2,6-dimethylphenoxy, 2,3,6-trimethylphenoxy, or 2,4,6-trimethylphenoxy. In a particularly preferred embodiment, each Q1 is oxygen; both R7 radicals taken together are an unsubstituted (CH2)m alkylidene radical, wherein m is 2 to 10; and each A18-21 moiety is independently an aryloxy moiety with at least one substituent on each aromatic ring ortho to the oxygen linkage, optionally further substituted, especially 2-methylphenoxy, 2,6-dimethylphenoxy, 2,3,6-trimethylphenoxy, or 2,4,6-trimethylphenoxy. In an especially preferred embodiment, each Q1 is oxygen; each R7 is methyl; and each A18-21 moiety is independently an aryloxy moiety with at least one substituent on each aromatic ring ortho to the oxygen linkage, optionally further substituted, especially 2-methylphenoxy, 2,6-dimethylphenoxy, 2,3,6-trimethylphenoxy, or 2,4,6-trimethylphenoxy.
In another embodiment of the invention, the phosphoramide comprises a phosphoramide having a glass transition point of at least about 0xc2x0 C., preferably of at least about 10xc2x0 C., and most preferably of at least about 20xc2x0 C., of the formula I: 
wherein Q1 is oxygen or sulfur, and R1 is of the formula X: 
wherein each Q1 is independently oxygen or sulfur; each of A22-24 is independently an alkyloxy, alkylthio, aryloxy, or arylthio residue, or an aryloxy or arylthio residue optionally containing at least one alkyl or halogen substitution, or mixture thereof; or an amine residue; each Z1 is an alkyl radical, aromatic radical, or aromatic radical containing at least one alkyl or halogen substitution or mixture thereof; each X1 is an alkylidene radical, aromatic radical, or aromatic radical containing at least one alkyl or halogen substitution or mixture thereof; n is from 0 to about 200; and R2 and R3 are each independently an alkyloxy, alkylthio, aryloxy, or arylthio residue, or an aryloxy or arylthio residue optionally containing at least one alkyl or halogen substitution, or mixture thereof; or an amine residue. In preferred embodiments each Q1 is oxygen, and each A22-24 moiety and each R2-3 moiety is independently phenoxy or a substituted phenoxy moiety. In more preferred embodiments each Q1 is oxygen, and each A22-24 moiety and each R2-3 moiety is independently an aryloxy moiety with at least one aryloxy moiety having at least one substituent on an aromatic ring ortho to the oxygen linkage, optionally further substituted. In still more preferred embodiments each Q1 is oxygen, and each A22-24 moiety and each R2-3 moiety is independently an aryloxy moiety with at least one substituent on each aromatic ring ortho to the oxygen linkage, optionally further substituted. In yet still more preferred embodiments each Q1 is oxygen, and each A22-24 moiety and each R2-3 moiety is independently an aryloxy moiety with at least two substituents on each aromatic ring ortho to the oxygen linkage, as for example a 2,6-disubstituted phenoxy moiety, optionally further substituted. Preferred substituents are C1-8 straight-chain or branched alkyl, or halogen. In an especially preferred embodiment, each Q1 is oxygen; each A22-24 moiety is independently phenoxy, 2-methylphenoxy, 2,6-dimethylphenoxy, 2,3,6-trimethylphenoxy, or 2,4,6-trimethylphenoxy; each Z1 is methyl or benzyl; each X1 is an alkylidene radical containing 2-24 carbon atoms; n is from 0 to about 5; and R2 and R3 are each independently phenoxy, 2-methylphenoxy, 2,6-dimethylphenoxy, 2,3,6-trimethylphenoxy, or 2,4,6-trimethylphenoxy.
In another embodiment of the invention, the phosphoramide comprises a phosphoramide having a glass transition point of at least about 0xc2x0 C., preferably of at least about 10xc2x0 C., and most preferably of at least about 20xc2x0 C., of the formula I: 
wherein Q1 is oxygen or sulfur; and R1 is of the formula XI: 
wherein each Q1 is independently oxygen or sulfur; each X2 is an alkylidene or alkyl-substituted alkylidene residue, aryl residue, or alkaryl residue; each Z2 is an alkylidene or alkyl-substituted alkylidene residue; each of R8, R9, and R10 is independently an alkyloxy, alkylthio, aryloxy, or arylthio residue, or an aryloxy or arylthio residue optionally containing at least one alkyl or halogen substitution, or mixture thereof; or an amine residue; n is from 0 to about 5; and R2 and R3 are each independently an alkyloxy, alkylthio, aryloxy, or arylthio residue, or an aryloxy or arylthio residue optionally containing at least one alkyl or halogen substitution, or mixture thereof; or an amine residue. In preferred embodiments each Q1 is oxygen, and each R8-10 moiety and each R2-3 moiety is independently phenoxy or a substituted phenoxy moiety. In more preferred embodiments each Q1 is oxygen, and each R8-10 moiety and each R2-3 moiety is independently an aryloxy moiety with at least one aryloxy moiety having at least one substituent on an aromatic ring ortho to the oxygen linkage, optionally further substituted. In still more preferred embodiments each Q1 is oxygen, and each R8-10 moiety and each R2-3 moiety is independently an aryloxy moiety with at least one substituent on each aromatic ring ortho to the oxygen linkage, optionally further substituted. In yet still more preferred embodiments each Q1 is oxygen, and each R8-10 moiety and each R2-3 moiety is independently an aryloxy moiety with at least two substituents on each aromatic ring ortho to the oxygen linkage, as for example a 2,6-disubstituted phenoxy moiety, optionally further substituted. Preferred substituents are C1-8 straight-chain or branched alkyl, or halogen. In a particularly preferred embodiment, each Q1 is oxygen; each X2 is an alkylidene or alkyl-substituted alkylidene residue; each Z2 is an alkylidene or alkyl-substituted alkylidene residue; each of R2, R3, R8, R9, and R10 is independently phenoxy, 2-methylphenoxy, 2,6-dimethylphenoxy, 2,3,6-trimethylphenoxy, or 2,4,6-trimethylphenoxy; and n is from 0 to about 5. In a more particularly preferred embodiment, each Q1 is oxygen; each X2 and Z2 is independently an unsubstituted alkylidene residue of the form (CH2)m, wherein m is 2 to 10; each of R2, R3, R8, R9, and R10 is independently phenoxy, 2-methylphenoxy, 2,6-dimethylphenoxy, 2,3,6-trimethylphenoxy, or 2,4,6-trimethylphenoxy; and n is from 0 to about 5. In especially preferred embodiments, the phosphoramide is derived from piperazine (i.e. X2 and Z2 are each xe2x80x94CH2xe2x80x94CH2xe2x80x94).
In another preferred embodiment, the phosphoramide comprises a cyclic phosphoramide having a glass transition point of at least about 0xc2x0 C., preferably of at least about 10xc2x0 C., and most preferably of at least about 20xc2x0 C. of the formula XII: 
wherein each of R11-14 is independently a hydrogen, an alkyl radical, or halogen, X3 is an alkylidene radical, Q1 is oxygen or sulfur, and A25 is a group derived from a primary or secondary amine having the same or different radicals that can be aliphatic, alicyclic, aromatic, or alkaryl, or A25 is a group derived from a heterocyclic amine, or A25 is a hydrazine compound. Preferably Q1 is oxygen. In preferred embodiments each Q1 is oxygen, and each of the two phenyl rings is independently at least a monosubstituted phenoxy moiety, wherein the at least one substituent is represented by the linkage to X3. In still more preferred embodiments each Q1 is oxygen, and each of the two phenyl rings is independently at least disubstituted wherein at least one substituent is represented by the linkage to X3. Preferred substituents R11-14, when present, are straight-chain or branched alkyl, or halogen. In a preferred embodiment R11-14 substituents on each aromatic ring are each 2,4-dimethyl or 2,3-dimethyl groups relative to the oxygen linkage. In a more preferred embodiment R11 and R13 are each methyl ortho to the oxygen linkage, and R12 and R14 are each hydrogen. In a still more preferred embodiment R11-14 are hydrogen. It should be noted that when n is 0, then the two aryl rings are linked together at that site (i.e. where X3 is absent) by a single bond in the positions ortho,ortho"" to the phosphoryl bonds.
In another preferred embodiment, the phosphoramide comprises a bis(cyclic) phosphoramide having a glass transition point of at least about 0xc2x0 C., preferably of at least about 10xc2x0 C., and most preferably of at least about 20xc2x0 C. of the formula XIII: 
wherein Q1 is oxygen or sulfur; each of R15-22 is independently a hydrogen, an alkyl radical, or halogen; X4 is an alkylidene radical; m and n are each independently 0 or 1; and A26 is 
wherein G1 is sulfur, an alkylidene radical, alkyl-substituted alkylidene radical, aryl radical, or alkaryl radical, and each Z3 is independently an alkyl radical, an aryl radical, or an aryl radical containing at least one alkyl or halogen substitution, or mixture thereof; or wherein A26 is 
wherein G2 is alkylidene, aryl, or alkaryl, and Y2 is alkylidene or alkyl-substituted alkylidene. In preferred embodiments each Q1 is oxygen, and each of the four phenyl rings is independently at least a monosubstituted phenoxy moiety, wherein the at least one substituent is represented by the linkage to X4. In still more preferred embodiments each Q1 is oxygen, and each of the two phenyl rings is independently at least disubstituted wherein at least one substituent is represented by the linkage to X4. Preferred substituents R15-22, when present, are straight-chain or branched alkyl, or halogen. In a preferred embodiment R15-22 substituents on each aromatic ring are each 2,4-dimethyl or 2,3-dimethyl groups relative to the oxygen linkage. In a more preferred embodiment R15, R17, R19, and R21 are each methyl ortho to the oxygen linkage, and R16, R18, R20, and R22 are each hydrogen. In a still more preferred embodiment R15-22 are hydrogen. Highly preferred phosphoramides include those wherein Q1 is oxygen; A26 is a residue of piperazine; the phosphoramide has a plane of symmetry through A26; R15-22 are hydrogen; n and m are each 1; and X4 is CHR23 wherein R23 is a hydrogen or an alkyl residue of from about 1 to about 6 carbon atoms. It should be noted that when either or both of m or n is 0, then the two aryl rings are linked together at that site (i.e. where X4 is absent) by a single bond in the positions ortho,ortho"" to the phosphoryl bonds.
Phosphoramides of useful molecular structure are preferably prepared by the reaction of a corresponding amine such as, for example, piperazine or N,Nxe2x80x2-dimethylethylenediamine with a diaryl chlorophosphate of the formula (aryl-O)2POCl in the presence of a tertiary amine. This method of preparation is described in Talley, J. Chem. Eng. Data, 33, 221-222 (1988) and leads to specific phosphoramide compounds without repeating units. Alternatively, phosphoramides may be prepared by the reaction of the corresponding amine with P(O)Cl3 in the presence of a tertiary amine, with the desired hydroxyl-or thiohydroxy-containing compound added simultaneously or subsequently to the addition of the amine. Addition of a diamine or triamine to P(O)Cl3 with simultaneous or subsequent addition of the hydroxyl or thiohydroxy-containing compound is believed to lead to repeating units of phosphoramide, often of 1 to about 5 phosphoramide linkages per compound. Similarly, addition of a diamine or triamine to a monosubstituted phosphoryl- or thiophosphoryl dichloride with simultaneous or subsequent addition of hydroxyl- or thiohydroxy-containing compound is also believed to lead to repeating units of phosphoramide. P(S)Cl3 may be substituted for P(O)Cl3 in the above preparations to provide suitable phosphoramides.
Another constituent of the resin compositions of the invention is at least one adjunct flame retardant compound. An adjunct flame retardant compound may be an organic or inorganic, polymeric or non-polymeric compound. In certain preferred embodiments an adjunct flame retardant is one which may promote char formation in at least one resinous constituent, for example in polycarbonate when polycarbonate is a blend constituent.
In one embodiment of the present invention the adjunct flame retardant comprises at least one polymeric or non-polymeric organic phosphorus species selected from the group consisting of phosphate esters, thiophosphate esters, phosphonate esters, thiophosphonate esters, phosphinate esters, thiophosphinate esters, phosphines, including triphenylphosphine, phosphine oxides, including triphenylphosphine oxide and tris(2-cyanoethyl)phosphine oxide, thiophosphine oxides, and phosphonium salts. Preferred organic phosphorus species are non-polymeric phosphate esters including, for example, alkyl phosphate esters, aryl phosphate esters, resorcinol-based phosphate esters, and bisphenol-based phosphate esters. Illustrative, non-limiting examples of such phosphorus species include triphenylphosphate, tricresylphosphate, resorcinol bis(diphenyl-phosphate), bisphenol A bis(diphenyl-phosphate), and other aromatic phosphate esters known in the art.
In another embodiment of the present invention the adjunct flame retardant comprises at least one polymeric or non-polymeric inorganic phosphorus salt with anions selected from the group consisting of phosphates, thiophosphates, phosphonates, thiophosphonates, phosphinates, thiophosphinates, pyrophosphates, and metaphosphates. The cations in these inorganic phosphorus salts comprise at least one cation selected from the group consisting of ammonium, alkyl-substituted ammonium, aryl-substituted ammonium, and mixed alkyl-aryl-substituted ammonium; alkali metal, lithium, sodium, potassium; alkaline earth metal, magnesium, calcium, barium; transition metal, zirconium, hafnium, iron, zinc; lanthanide metal, lanthanum; boron; aluminum; and tin. Preferred inorganic phosphorus species are non-polymeric phosphate salts including, for example, alkali metal phosphates, boron phosphate, aluminum phosphate, and zinc phosphate.
In another embodiment of the present invention the adjunct flame retardant comprises at least one polymeric or non-polymeric sulfur species selected from the group consisting of sulfonate salts, sulfinate salts, sulfones, sulfoxides, and sulfides. Illustrative, non-limiting examples of such polymeric or non-polymeric sulfur species include polyarylene sulfide, polyarylene sulfide-sulfones, and salts of sulfonated aromatic compounds. Preferred sulfur species are polyphenylene sulfide, polyphenylsulfone, sodium para-toluene sulfonate, potassium diphenylsulfone-3-sulfonate, and Reimer""s salts, including potassium perfluorobutane sulfonate.
In another embodiment of the present invention the adjunct flame retardant comprises at least one polymeric or non-polymeric boron-containing species. Illustrative, non-limiting examples of such species include zinc borate, boron phosphate, borax, and boric acid. Zinc borate is a particularly preferred boron-containing species.
In yet another embodiment of the present invention the adjunct lame retardant comprises at least one polymeric or non-polymeric antimony salt selected from the group consisting of oxides, halides, sulfides, sulfonates, phosphates, phosphonates, and carboxylates. Illustrative, non-limiting examples of such polymeric or non-polymeric antimony salts include antimony oxide, antimony trichloride, and antimony potassium tartrate. A particularly preferred antimony salt is antimony oxide.
In yet another embodiment of the present invention the adjunct flame retardant comprises at least one polymeric or non-polymeric silicone compound. Polymeric silicone compounds are often preferred. In one embodiment of the present invention particularly preferred polysiloxanes are those containing a plurality of dimethylsiloxane units, and, optionally, a minor proportion of organic groups, including but not limited to, at least one of vinyl, hydrogen, epoxy, amine, phenyl, and the like. For certain embodiments suitable polymeric silicone compounds include SF1706 and SF1708 available from General Electric Silicones. In another embodiment further preferred polysiloxanes are those which have first units of RSiO1.0 and second units of RSiO1.5 where R is a radical selected from the group consisting of saturated and aromatic ring hydrocarbon groups as disclosed in European Patent Application 829,521, which is incorporated herein by reference.
In another embodiment of the present invention the adjunct flame retardant comprises at least one organoclay. Examples of compositions containing organoclays are disclosed in copending, commonly owned application Ser. No. 09/032,533, filed Feb. 27, 1998.
As used herein, xe2x80x9corganoclayxe2x80x9d means a layered clay, usually a silicate clay, derived from a layered mineral and in which organic moieties have been incorporated, ordinarily by ion exchange and especially cation exchange with organic ions and/or onium compounds. Illustrative organic ions are mono-and polyammonium cations such as trimethyldodecylammonium and N,Nxe2x80x2-didodecylimidazolium.
Illustrative layered minerals are the kaolinites and the montmorillonites. It is also possible to employ minerals of the illite group, including hydromicas, phengite, brammallite, glaucomite, cejadonite and the like. Often, the preferred layered minerals include those often referred to as 2:1 layered silicate minerals, including muscovite, vermiculite, saponite, hectorite and montmorillonite, the latter often being most preferred. The layered minerals may be synthetically produced, but most often they are naturally occurring and commercially available. A detailed description of suitable layered minerals can be found in U.S. Pat. No. 5,530,052, the disclosure of which is incorporated by reference herein.
Suitable specific commercially available or easily prepared organoclays which are illustrative of those which may be employed include CLAYTONE HY, a montmorillonite which has been cation exchanged with dimethyidi(hydrogenated tallow)ammonium ion, and CLAYTONE APA, a montmorillonite which has been cation exchanged with methylbenzyldi(hydrogenated tallow)ammonium ion, both available from Southern Clay Products; and montmorillonite which has been cation exchanged with such ions as dodecylammonium, trimethyldodecylammonium, N,Nxe2x80x2-didodecylimidazolium, N,Nxe2x80x2-ditetradecylbenzimidazolium or methylbis(hydroxyethyl)-(hydrogenated tallow)ammonium.
In one embodiment of the invention the combination of adjunct flame retardant and at least one phosphoramide having a glass transition point of at least about 0xc2x0 C. results in a flame retardant composition having a UL-94 rating of V-2, V-1, or V-0. In another embodiment of the invention the presence of certain amounts of adjunct flame retardant permits the use of a lesser amount of at least one phosphoramide having a glass transition point of at least about 0xc2x0 C. without substantial loss in flame retardant properties of the composition. Without substantial loss in flame retardant properties of the composition means that the UL-94 rating for the composition does not become worse in the presence of phosphoramide/adjunct flame retardant combination compared to that rating observed in the absence of adjunct flame retardant. A UL-94 rating becomes worse, for example, when it increases from V-0 to either V-1 or V-2, or when it increases from V-1 to V-2. In yet another embodiment of the invention the flame retardant properties of the composition become better in the presence of phosphoramide/adjunct flame retardant combination compared to those observed in the absence of adjunct flame retardant. Better flame retardant properties mean that either the flame out time (defined hereinafter below) for the composition decreases and/or that the UL-94 rating for the composition improves, for example, from V-2 to either V-1 or V-0, or from V-1 to V-0. In still another embodiment of the invention a synergistic effect on composition properties, particularly flame retardant properties, is observed in the presence of the phosphoramide/adjunct flame retardant combination compared to that observed in the presence of at least one phosphoramide or adjunct flame retardant alone.
The resinous compositions of this invention may contain a flame retarding amount and/or processability enhancing amount of the combination of at least one phosphoramide and adjunct flame retardant. Flame retardancy may be measured according to the Underwriters"" Laboratory UL-94 protocol. In this embodiment a flame retarding amount is an amount effective to render the composition at least a V-2 rating, preferably at least a V-1 rating, and most preferably a V-0 rating after testing in the UL-94 protocol when measured on a test specimen of about 0.03 to about 0.125 inch in thickness by about 0.5 inch by about 5 inch, preferably about 0.125 inch in thickness by about 0.5 inch by about 5 inch, more preferably about 0.06 inch in thickness by about 0.5 inch by about 5 inch, and most preferably about 0.03 inch in thickness by about 0.5 inch by about 5 inch dimensions. Enhanced processability can be determined, for example, as a reduction in extruder torque during compounding, reduced pressure in injection molding, reduced viscosity, and/or decreased cycle time.
In addition there are many different government-mandated tests for evaluating the fire resistance of thermoplastics, such as polycarbonate sheet building materials. One of the more aggressive tests is French norm NF-P-92-505 (Norme Francaise NF-P-92-505 of L""Association Francaise de Normalisation (AFNOR), Paris, France). In this test, a radiator is placed above a specimen of the test material supported on a grid. Cotton wool is placed in a receptacle below the test material. During the test, the radiator is turned on for 10 minutes, and droplets from the specimen may fall through the grid onto the cotton wool. If the cotton wool burns, the specimen is considered as failing the test.
Therefore, in still another embodiment the resinous compositions of this invention may contain an amount of the combination of at least one phosphoramide and at least one adjunct flame retardant effective to provide at least a 50% pass rate in ten test specimens in French flammability test NF-P-92-505 when measured on test specimens with density between about 1.2 to about 6.0 kilograms per square meter. For typical sheet material test specimens comprising bisphenol A polycarbonate a density between about 1.2 to about 6.0 kilograms per square meter corresponds to a thickness of between about 1.0 to about 5.0 millimeters. In a preferred embodiment a test specimen comprising bisphenol A polycarbonate has a density of about 3.6 kilograms per square meter and a corresponding thickness of about 3 millimeters.
Typically, a flame retarding amount of the combination of at least one phosphoramide and at least one adjunct flame retardant in the compositions of the invention is in the range of about 0.008-5 parts, preferably about 0.1-2.5 parts, of phosphorus per 100 parts of resinous materials (phr), all percentages herein being by weight. In especially preferred embodiments a flame retarding amount of the combination of at least one phosphoramide and at least one adjunct flame retardant in the compositions of the invention is in the range of about 0.05-0.2 parts of phosphorus per 100 parts of resinous materials (phr). The total amount of phosphoramide and adjunct flame retardant is most often in the range of about 0.1-50 phr, preferably about 0.5-35 phr, and more preferably about 1-25 phr.
In one embodiment of the present invention halogen-containing flame retardants or other halogen-containing species may also be present in the compositions as adjunct flame retardants. In many resinous compositions, the combination of a halogen-containing flame retardant and at least one phosphoramide (or mixture of phosphoramide with another adjunct flame retardant), particularly including a phosphoramide having a glass transition point of at least about 0xc2x0 C., provides both suitable flame retardant properties and unexpectedly improved high temperature properties (such as measured, for example, by HDT or Tg of a resinous phase). Illustrative, non-limiting examples of halogen-containing flame retardants or halogen-containing species include brominated flame retardants and phosphoramides containing halogenated aromatic substituents. Due to environmental regulations chlorine-free and bromine-free compositions may be preferred for certain applications. Therefore, in a preferred embodiment the present invention includes compositions comprising a thermoplastic resin, at least one phosphoramide having a glass transition point of at least about 0xc2x0 C., and an adjunct flame retardant, said compositions being essentially free of chlorine and bromine. In this context essentially free means that no chlorine- or bromine-containing species has been added to the compositions in their formulation. In another of its embodiments the present invention includes articles obtained from said chlorine-free or bromine-free compositions.
The compositions of the invention may also contain other conventional additives including stabilizers, inhibitors, plasticizers, fillers, mold release agents, and anti-drip agents. Anti-drip agents are illustrated by tetrafluoroethylene polymers or copolymers, including mixtures with such other polymers as polystyrene-co-acrylonitrile (sometimes referred to herein as styrene-acrylonitrile copolymer).
A principal characteristic of preferred compositions of the invention is their improved high temperature properties. These are demonstrated by the fact that the decrease in glass transition temperature (Tg) exhibited as a result of the incorporation of a phosphoramide in the composition is substantially less than the corresponding decrease exhibited in blends containing, for example, phosphate esters such as bis(diaryl phosphates) of dihydroxyaromatic compounds. This is evident when a phosphoramide is compared to the organic phosphate ester in amounts suitable to provide enhanced flame resistance when measured, for example, in the UL-94 test procedure. In the case of phase-separated blends such as polycarbonate-ABS blends, the decrease in Tg is noted in the polycarbonate phase.
Experience has shown that the flame retarding properties of a phosphorus-based compound included in a resinous composition are generally proportional to the amount of phosphorus in the composition rather than to the amount of the compound itself. Thus, equal weights of two additives having different molecular weights but the same flame retarding properties may produce different UL-94 results, but amounts of the two additives which contribute the same proportion of phosphorus to the resinous composition will produce the same UL-94 results. On the other hand, other physical properties such as high temperature resistance are dependent on the amount of the compound itself and relatively independent of the phosphorus proportion therein. For this reason, the dependence of flame retarding and high temperature resistance of compositions containing two phosphorus-based compounds may not follow the same pattern.
It has been shown, however, with respect to the preferred phosphoramides employed according to the present invention that their superior properties of flame retardance and high temperature resistance are consistent. Thus, for example, proportions of resorcinol bis(di-2,6-xylyl phosphate) effective to confer a suitable flame-out time on certain resinous compositions are similar to those produced by a typical bis(2,6-xylyl)-phosphoramide at an essentially equivalent level of phosphorus, but the bisphosphoramide has a substantially lower tendency to decrease heat deflection temperature (HDT) despite the slightly greater amount of the bulk additive.
It should be clear that the present invention also affords methods to increase the heat distortion temperature of flame resistant compositions containing an amount of at least one phosphoramide and at least one adjunct flame retardant effective to render the composition a flame rating of at least V-2, preferably of at least V-1, most preferably V-0, in the UL-94 protocol, wherein the method comprises combining at least one thermoplastic resin, at least one phosphoramide having a glass transition point of at least about 0xc2x0 C., preferably of at least about 10xc2x0 C., and most preferably of at least about 20xc2x0 C.; and at least one adjunct flame retardant. In a preferred embodiment the invention also affords methods to increase the heat distortion temperature of chlorine-free and bromine-free, flame resistant compositions as described in the previous sentence. The method may be used to increase the heat distortion temperature of compositions comprising essentially a single phosphoramide or a mixture of two or more different types of phosphoramide; and those comprising essentially a single adjunct flame retardant, or a mixture of two or more different types of adjunct flame retardant. Compositions containing essentially a single phosphoramide and a single adjunct flame retardant are often preferred. Useful thermoplastic resins have been described herein. Especially preferred thermoplastic resins are polycarbonate, most especially bisphenol A- based polycarbonate, and blends of polycarbonate, especially polycarbonate-SAN-ABS blends, and polycarbonate-ABS blends, in which the amount of ABS may typically vary from about 1 to about 45 wt. %. An especially preferred phosphoramide is N,Nxe2x80x2-bis-[di-(2,6-xylyl)-phosphoryl]-piperazine. It should also be clear that the present invention includes compositions made by the methods as well as articles made from the compositions.
Preparation methods for the compositions of the invention are typical of those employed for resinous blends. They may include such steps as dry blending followed by melt processing, the latter operation frequently being performed under continuous conditions as by extrusion. Following melt processing, the compositions are molded into test specimens by conventional means such as injection molding.
The addition of at least one phosphoramide and at least one adjunct flame retardant to the compositions of the present invention may be by mixing all of the blend components together prior to melt processing. Alternatively, either one of, or both of at least one phosphoramide and at least one adjunct flame retardant may be combined with at least one resinous blend component as a concentrate in a prior processing step. Such concentrates are often made by melt processing. The concentrate may then be combined with the remaining blend components.
The various embodiments of the invention are inclusive of simple blends comprising at least one thermoplastic resin and at least one phosphoramide and at least one adjunct flame retardant, and also of compositions in which one or more of said materials has undergone chemical reaction, either by itself or in combination with another blend component. When proportions are specified, they apply to the originally incorporated materials rather than those remaining after any such reaction.
In another of its embodiments the present invention comprises articles of manufacture made from the instantly disclosed compositions. Such articles may be transparent, translucent, or opaque depending upon the blend composition. Said articles can be made by any convenient means known in the art. Typical means include, but are not limited to, injection molding, thermoforming, blow molding, and calendering. Especially preferred articles include indirect and direct wound deflection yokes for all cathode ray tube applications including television and computer monitors, slit type deflection yokes, mold coil deflection yokes, television backplates, docking stations, pedestals, bezels, pallets, electronic equipment such as switches, switch housings, plugs, plug housings, electrical connectors, connecting devices, sockets; housings for electronic equipment such as television cabinets, computer housings, including desk-top computers, portable computers, lap-top computers, palm-held computers; monitor housings, printer housings, keyboards, FAX machine housings, copier housings, telephone housings, mobile phone housings, radio sender and/or receiver housings, lights and lighting fixtures, battery chargers, battery housings, antenna housings, transformers, modems, cartridges, network interface devices, circuit breakers, meter housings, panels for wet and dry appliances such as dishwashers, clothes washers, clothes dryers, refrigerators; heating and ventilation enclosures, fans, air conditioner housings, cladding and seating for indoor and outdoor application such as public transportation including trains, subways, buses; automotive electrical components; articles used in glazing applications, such as roofs, greenhouses, sunrooms, swimming pool enclosures, windows.
The invention is illustrated by the following examples. All parts and percentages are by weight. Intrinsic viscosity was determined in chloroform at 25xc2x0 C. HDT values were determined at 264 psi (1820 kPa) according to ASTM procedure D648.